The present invention relates generally to optical communications, and more particularly, to dynamic multidimensional optical networking based on spatial and spectral processing.
In current optical networks, the need to establish lightpaths in arbitrary directions, and switch them on-demand has led to the adoption of photonic routing devices mostly in the form of reconfigurable optical add-drop multiplexers (ROADM), and photonic crossconnects (PXC). With such technologies, optical switching and routing can be done at or above the per-wavelength level (i.e. “at the fiber level”). However, these optical switching and routing principles can only operate at per-wavelength or per-fiber granularity, which significantly limits flexibility and reduces bandwidth efficiency in future mixed-rate, heterogeneous optical networks with predominantly dynamic traffic demands. For example, switching at fiber-level granularity may cause unnecessary re-direction of certain wavelengths, which can result in substantial bandwidth waste. Conversely, switching at the wavelength level enables finer granularity, but could insert unnecessary complexity to the overall ROADM design.
Switching at interim granularity, so called “waveband switching”, has been considered for some time as a more practical alternative. However, this previously proposed concept has assumed that waveband consists of a number of wavelengths aligned to an ITU-T defined wavelength grid. With the introduction of optical orthogonal frequency division multiplexing (OFDM), novel frequency-domain degrees of freedom have been added to the waveband switching approach, and are exploited in this work. Moreover, with the advent of multicore and multimode optical fibers for throughput maximization, coarse switching at the fiber level may now require that the overall wavelength spectrum be switched not just from one fiber to another, but from one fiber core to another. While previous work has considered physical-layer benefits of multimode and multicore fiber transmission, to the best of our knowledge, no previous work exists on exploiting this spatial dimension for optical networking (i.e. switching and routing).
Accordingly, there is a need for. dynamic multidimensional optical networking based on spatial and spectral processing